1. Field of the Invention
The present invention relates to a process for two-stage injection molding of an air-conditioning blow-out port device mounted in an instrument panel in an automobile, and particularly, to a process for two-stage injection molding of an air-conditioning blow-out port device comprising a housing of synthetic resin, which includes pairs of shaft bores provided in a coaxial arrangement in opposed wall portions of a peripheral wall to extend through the opposed wall portions, and a plurality of blades of synthetic resin which each include a pair of support shafts projectingly provided at opposite ends of a blade body disposed within the housing and rotatably fitted in the shaft bores.
2. Description of the Prior Art
There is a conventionally known two-stage injection molding process of this type, which comprises forming a housing at a primary injection step, and forming blades by using the shaft bores in the housing as support shaft-forming cavities and then bringing ejector pins into abutment against, for example, an end face of the housing, thereby releasing a resulting blow-out port device.
With the above prior art process, the releasing of the housing is superior, because it has been set in opening/closing dies in the secondary injection molding step, whereas the releasing of the blades is inferior, because they have been formed at the second injection molding step to closely adhere to a molding surface.
With the prior art process, if the die opening is performed under such a situation after the secondary injection molding, the support shaft of each blade may be bent or broken in some cases, because no retaining means is provided between the housing and one of opening/closing dies which must be intrinsically stationary, and hence, the housing follows the other opening/closing die, while each of the blades is in close adhesion to the one opening/closing die. In releasing the device from the dies, each of the blades is pushed out through the housing and hence, a large burden is applied to each of the support shafts, likewise resulting in a problem of a damage to each support shaft, which may damage the blade body.
Accordingly, it is an object of the present invention to provide a two-stage injection molding process of the above-described type, wherein the damages to each of the blade bodies and each of the support shafts can be avoided.